Sandwich-type electrochemical aptasensor based on HMCS@PDA@AuNPs and PtCu DNs/MUN-CuO-TiO2 for ultrasensitive detection of cardiac troponin I

Abstract

The key to diagnosing acute myocardial infarction (AMI) lies in the sensitive and accurate analysis of cardiac troponin I (cTnI) content in human blood. Herein, in order to detect the content of cTnI, a novel sandwich-type cTnI electrochemical aptasensor was developed by utilizing dendritic platinum-copper alloy nanoparticles loaded on graphene-like CuO-TiO2 mesoporous ultrathin nanosheet (PtCu DNs/MUN-CuO-TiO2) as label material, and AuNPs loaded on polydopamine modified hollow mesoporous carbon spheres (HMCS@PDA@AuNPs) as electrode-modified material. On the one hand, with its advantages of assistance of Au and PDA coating, abundant pore structure, and large specific surface area, the HMCS@PDA@AuNPs exhibited excellent electronic conductivity but with a low catalytic capacity for the reduction of H2O2, thus enhancing the sensitivity of aptasensor. On the other hand, because of combining the structural and electrochemical performance superiority of MUN-CuO-TiO2 and PtCu DNs, such as short electron transfer distance and abundant reactive sites, the catalytic performance of obtained PtCu DNs/MUN-CuO-TiO2 towards H2O2 reduction was enhanced and realized signal amplification. The constructed electrochemical aptasensor for cTnI detection exhibited a satisfactory dynamic range from 0.01 pg/mL to 500.0 ng/mL and a lower detection limit of 2.3 fg/mL. The recommended sensor has been utilized to detect human serum samples with acceptable results, exhibiting potential for clinical application.